To an increasing extent, plate-like or strip-like substrates are being assembled with leadless components, instead of wire-equipped components, as before; these leadless elements will hereinafter be called chip components. The term "chip components" refers not only to cube-shaped chip resistors and chip capacitors, but to all "leadless" components, such as all planar components, the leads of which are not "inserted" into the substrate but are instead "mounted" on it (examples are MELFS, circuits in an SO housing, a DIL housing, and so forth).
As compared with the use of wire-equipped components, the use of chip components results in greater packing density and greater reliability and in assembly techniques that are more amenable to being automated.
To mount chip components onto substrates automatically, automatic component mounting machines have meanwhile been developed, the basic structure of which comprises a substrate holder, a "pick-and-place" device including a positioning unit and a mounting head, and a component delivery device.
Chip components are supplied by component manufacturers either in bags or in belts wound up on belt reels. When chip components furnished in bags are used, the component delivery apparatus of automatic component mounting machines includes a longitudinal vibration conveyor, a round vibration conveyor or a rectangular vibration conveyor, for example. If chip components furnished in belts wound up on belt reels (known as belted components) are used, then the component delivery apparatus of automatic component mounting machines includes a holder unit for the belt reels, a belt guide having a plurality of belt guide tracks, a belt conveyor and a peel-off unit for the material covering the belt.
To define the prior art which is the point of departure for the present invention, specifically with respect to chip components, the automatic mounting of chip components onto substrates and automatic component mounting machines, reference is hereby made to the Siemens publication entitled "Bestuckautomat fur Chip und planare Bauelemente" ["Automatic Mounting Machine for Chip and Planar Components"], Siemens publication Mch 01710.835. The entire disclosure content of this publication is hereby expressly incorporated by reference into the disclosure content of this patent application.
In the prior art which is the point of departure for the invention (see the above-mentioned Siemens publication, in particular page 8, left-hand column; page 9, left-hand column; pages 1-16; and pages 21 ff.), the chip delivery apparatus is embodied such that a separate belt guide, a separate belt conveyor unit and a separate peel-off drive mechanism are provided for each belt reel (or each pair of belt reels). In the assembled state, the holder unit for the belt reels, the belt guides, the belt conveyor unit and the peel-off unit along with the peel-off drive mechanisms form a stationary unit.